Russia forming a united nuclear energy holding with Ukraine that will allow Ukrainian nuclear companies to enter the Russian market and create possibilities for joint work in third countries, the Russian premier said.

"We are offering full-scale cooperation in our nuclear energy sectors. We propose the formation of a major holding that would include unification of nuclear power generation, unification of nuclear equipment construction and of the nuclear cycle," Vladimir Putin said at a meeting with Ukrainian President Viktor Yanukoovych.

Yanukovych said Ukraine is interested in Russia's proposals concerning cooperation in the nuclear energy sector, upgrading nuclear power stations and the unification of nuclear power generation.

"This is a very interesting proposal to form an enterprise for production of nuclear fuel not only for our [Ukrainian and Russian] nuclear power stations, but for third countries as well," Yanukovych told Putin.

"We might also cooperate in upgrading nuclear power stations, while the unification of nuclear power generation is an issue that was discussed in general terms for future implementation," he added.

Vladimir Putin arrived for an official visit in the capital of Ukraine, Kiev, late on Monday night.

Yanukovych, who was inaugurated as president in February, vowed during his campaign to improve relations with Russia and renegotiate the January 2009 deal on gas supplies, which increased the price, straining Ukraine's already troubled finances.